The present invention relates to a bolt assembly with improved rotating locking head.
Rotating bolts are found in gas-operated, recoil-operated, bolt action, lever-action and pump-action weapon designs.
A rotating bolt typically comprises a rotating head provided with lugs or radial lugs that engage seats provided in the barrel extension.
Generally, the rotating head can move with respect to the body of the bolt by means of a system with a pivot and a helical cam that imparts a combined rotary and translational motion to the rotating head.
Systems are known in which the helical cam is formed in the rotating head and others are known in which the helical cam is formed in the body of the bolt and engages a radial pivot that is integral with the bolt body, in the first case, and integral with the rotating head, in the second case.
EP0128125 discloses a bolt assembly of the type described above which has had, and continues to have, widespread application.
EP1130350 discloses a breechblock with a rotating head wherein a forcibly controlled stopping means, associated with the breechblock sleeve, blocks the angular momentum which effects the locking of the breechblock.
DE713126 discloses a breechblock for a machine-gun having an auxiliary spring adapted to accelerate the closure motion of the head.
Conventional rotating head bolts, applied to hunting rifles, in fact have shown some anomalies in operation due to particular situations that can occur during hunting activities.
It has been observed that, when carrying the rifle on one's shoulder with the muzzle directed upward, due to an impact, for example caused by the hunter jumping over a ditch, the rotating head might disengage from the locked position, ready for firing. That happens because the rotating head is not blocked by the recovery spring and is able to retract, with the lugs disengaging from the seats of the barrel extension.
If this occurs, and the hunter does not notice, when it is time to fire, the bolt is not locked and the firearm will not fire. If the animal does not flee immediately, certainly it flees when it hears the forced re-locking of the bolt by the hunter.
In order to lock the bolt manually, the hunter has to act on it, moving it backward and then sharply pushing it forward, to ensure that the rotating head returns to the locked position.
An additional problem of such action is that, in general, it is not easy to lock the bolt with a slow and quiet motion, because the rotating head tends to stop in the position that corresponds to the entry plane of the seats provided in the barrel, without completing the locking, because the lugs or lugs of the rotating head are not aligned with said seats. This occurs because the rotating head lacks the residual energy to complete the rotation and translation needed to allow the insertion of the lugs in the seats of the barrel.
Such problem may occur if the hunter wishes, for example, to change the cartridge to adapt it to the target that becomes available and must do so silently to avoid startling the animal. However, the hunter might be unable to re-load the firearm with a slow and consequently silent motion and might be forced to push the bolt sharply into the locking position, thus startling the animal and causing the target to flee.